Wide area network (WAN) devices include, but are not limited to, routers and gateways, which can be used to connect multiple computers to a WAN, and universal serial bus (USB) adapters (i.e., “USB dongles”), which are attached to computers via USB ports and are typically used to connect a single computer to a WAN.
Broadband access via wireless networks (e.g., code division multiple access (CDMA), universal mobile telecommunications systems (UMTS), wideband (W)-CDMA, long term evolution (LTE), and worldwide interoperability for microwave access (Wi-Max), etc.) provide the capabilities of mobility for use with portable notebook computers and hand-held devices, but bear the disadvantages of a higher rate of loss of wireless signal and Internet connectivity as compared to fixed-line networks.
In operation, when a computer executes a software to communicate with a remote party on the network (e.g., uses web browser software to communicate with a web server on the Internet), data traffic (e.g., Internet Protocol or “IP” traffic) is sent back and forth packaged with source and destination IP addresses in the header of each data packet.
In conventional networks, it is common practice to hide entire Internet Protocol (IP) addresses of a local area network (LAN), which usually includes a pool of private IP addresses shared by multiple computers, behind a single typically public IP address owned and/or used by a router. In operation, the route may route data traffic back and forth between the computers and the Internet. The router has a dynamic host configuration protocol (DHCP) server that manages the pool of private IP addresses, assigning them to end user devices as requested, and taking them back from the end-user devices when the addresses are no longer needed and returning them the pool. The amount of time a private IP address is assigned to a computer is called the “lease time.”
Extending the lease time for each computer requires a series of communication signals being sent back and forth with the DHCP server in the WAN device. In conventional WAN networks, in which the WAN device may direct data traffic for a large number of devices, the lease time is typically set at a long time interval of a day or more to reduce the volume of such communication signals being transferred back and forth. In common practice, Internet servers, for example, that host a given requested website never receive the private IP address of a given end-user computer. In fact, they only receive the public IP address of the WAN device through which the computer's request is routed. This IP mapping or transition process is typically accomplished by modifying the IP address information in IP data packets while in transit across a WAN device, such as a router. This process is generally referred to as network address translation (NAT). The privately originated IP address in the header of the end-user computer's request is “translated” into the publicly originated IP address of the router itself for routing or use across the Internet.
Some web-based software, however, does not function reliably or sometimes at all when NAT is applied, and may require a public IP address to function properly. A widespread solution to this problem is to implement a different IP translation operation known as “IP pass-through”, which entails both the sharing of the public IP address of the WAN device with a separate computer and the forwarding of all incoming traffic without modification from an incoming port on the public WAN-side of the router to an outgoing port on its private LAN-side connected to the computer (and vice-versa). This effectively allows each end-user device operating on the LAN to use the router's public IP address as the computer device's own IP address, without undergoing a NAT. The origination IP address in the header of data packets sent from the computer that is “behind” a WAN device, such as the router, operating in IP pass-through mode will be the same as the shared public IP address of the WAN device.
A problem with the user of IP pass-through, however, is that the management of the WAN device may be precluded from an end-user computer. Device management is necessary to manage a WAN device's status, diagnose problems and handle customer complaints. For device management to be possible, the WAN device and computer must be capable of direct communication with each other, which requires the WAN device to have its own private IP address separate from that of the computer on the LAN side. If IP pass-through is in being used and the WAN device and computer share a same IP address, then no device management communications are sent back and forth between the computer and the WAN device. The destination IP address of the device management data sent by the computer intended for the WAN device is identical to the “passed-through” IP address of the computer itself, and thus no IP traffic ever leaves the computer. In addition, in order for device management to be possible using continuous IP pass-through as it is conventionally used, the device management software must be installed directly on the computer, and the communications between the computer and the WAN device must be transmitted via a special channel other than a network interface. This burdensome configuration is called a “hosted” solution, because the solution must be run on the host computer.
Similarly, for an Internet service provider (ISP) operator to manage the WAN device from a network management server, the device and the server must also be able to directly communicate with each other. In this case, the IP traffic for device management must be received and processed by the WAN device itself. If IP pass-through is being used and all such device management IP traffic sent by the network management server is forwarded by the WAN device to the end-user computer, then the ISP operator cannot manage the WAN device. Specialized device management software tools may used to intercept the device management traffic by the WAN device and allow the management of the WAN device by operators even while IP pass-through mode is operating.
An additional problem with the above-described IP pass-through operation in the mobile WAN context arises from the fact that, wireless networks inherently suffer from a higher rate of loss of wireless signal and Internet connectivity, in general. When a WAN device loses connectivity with the Internet, the end-user computer's “passed-through” IP address becomes ineligible to be used for Internet communication purposes. The computer, however, does not recognize that the WAN access and the computer itself have been disconnected. As a result, the computer will continues to send its data traffic to the network through the WAN device, but that traffic is no longer passed-through to the intended website server, and will typically be dropped (i.e., lost).
Another problem is that any detour capabilities a computer with multiple network interfaces might normally have to route IP traffic from a lost or slower interface to a faster interface will also be impaired as a result of the loss in the WAN connectivity. This results in a significant slow down and/or interruption for the computer's WAN connectivity, and thus significantly lowers the quality of a wireless mobile device user's Internet session.